San Francisco Muni operators would get a 14.25 percent raise over three years, enough to cover increased pension costs to the workers while also offering a pay boost, according to a tentative agreement announced Monday.

It appeared to be an agreement on wages and pension costs that both sides could live with, while extending the contract to three years rather than two as previously proposed.

Former San Francisco Mayor Willie Brown was the key to the agreement between the MTA and Transport Workers Union Local 250-A, which had said Friday evening that there was a tentative agreement. With the contract set to expire, Brown stepped in at the request of Mayor Ed Lee and helped the two sides reach an agreement, something that months of bargaining and a three-day sickout by drivers failed to do.

Lee asked Brown, who writes a Sunday column for The Chronicle, to step in a couple of weeks ago, Reiskin said.

There was reportedly no talk of compensation for Brown's mediation role.

"I feel like I owe him something," Reiskin said, smiling broadly after the MTA meeting. "We have labor peace at the moment."

Brown would not comment.

The proposed contract's 14.25 percent raise would more than cover the 7.5 percent that employees would pay into their pension. All the increased pension payments and raises would be phased in over the three years of the contract.

The previous contract offer, rejected by the drivers, would have boosted pay by 11.25 percent over two years and would have made Muni drivers the second-highest paid transit workers in the country at around $32 an hour, according to the MTA. It was not clear Monday where they would rank under the proposed contract.

Union officials presented the contract terms to workers Monday night, with a vote scheduled for July 7. If approved, the MTA would vote on the contract July 15.

Drivers leaving the Monday meeting had mixed reactions to the terms. Some were angry, cursing as they walked out of the building. Others said they would vote for the contract.

"This is the best we're going to get," driver Blanca Contreras said. "I don't think the city is going to offer anything better.

Eric Williams, president of TWU Local 250-A, said he was confident the contract would be approved. "Our members will have an opportunity to voice their opinion with their vote," he said.

The operators overwhelmingly rejected an earlier contract agreement May 30, and then hundreds of drivers called in sick. Like all San Francisco city employees, Muni operators are prohibited from striking.

During the three-day sickout, which the union said it did not organize or sanction, the transit agency had to cancel about two-thirds of its bus, streetcar and Metro runs and all cable car service on the first day. While more drivers reported to work the next two days, the transit system was still hobbled by what was reportedly a grassroots protest by operators.

Negotiations remained tense before Brown's involvement, and union officials refused to enter an arbitration process adopted by voters in 2010. MTA officials threatened to withhold raises, stop collecting union dues and eliminate grievances if an agreement was not reached by Monday.

The previous contract offer, rejected by operators, would have required them to contribute 7.5 percent to their pension plans while offering a 5.05 percent pay increase. It also offered a 3.25 percent raise on July 1 and a raise of between 2.25 percent and 3.25 percent in 2015. Union representatives said the offer amounted to a pay cut.

City officials said they believed the "creative agreement" would be approved by both the operators and the MTA board.